Here are the source files for Project MRI:
I found some funny emails on the project, copied below for your
entertainment:
“I just had a most exhilarating experience: my
first MRI (on my lower back). This was amazing. I laid down on a sliding
table, and they pushed me into a sarcophagus like tube with mere inches around
my entire body. They put large headphones on my head, and then for the
next 30 minutes I was eased into a seemingly euphoric and meditative state. What
I heard were a series of interesting sounds...from jackhammer-like hammering, to
buzzing or vibrating cycles, bizarre sci-fi industrial like sounds, and so on.
It was delightful. The MRI technician said it was a rarity for someone to
actually enjoy that procedure. At one point in time, I was in a half
waking/dream state and was awoke by my leg twitching. I could have stayed
in there most of the day. And the amazing thing is that when I asked about the
source of the sounds, he said they were not mechanically generated; rather,
around my body, encased in metal, was a giant electrical coil surrounded by
helium, chilled down to a cool minus 270 degrees. The sounds were a result
of changes they were making in the electrical current and the resulting
vibrations to the machine. Unbelievable...not sure how all that produces an
image of my back, however.
...anyway, I started thinking, I would love to have
that 30 minutes captured on a digital recorder so that I could use it for
looping or as an ambient backdrop to my more experimental looping.
Are there any MRI technicians on the
list?”
Kris
”The machine I was encased in wasn't
unbearable at all...in fact, with the
firearm shooting headphones (exactly
this, in fact, but modified with the
plastic tube from the control room), the
sound was perfect. Those firearm
headphones filter out a lot of high end, and
what I heard with them on was
exquisite...no more or less louder than the
volume that I use for listening
to music. I wish I had turned the
lights off in the dressing room when I
removed the pants they provided,
however, because the static electricity was
unbelievable.
In light of
the question, where's the melody...I did discern tones, albeit
very constant
and industry like. I concur with Edward's comments about it
sounding like a
strange sci-fi moving. In fact, it sort of reminded me of
Forbidden Planet
and the scene where they were taking a tour of that
monstrous facility under
ground with all the automated machinery developed
by
aliens.”
Kris
Kris
Auditory System: Auditory stimuli are presented
during scanning via a high-fidelity system designed for the MR environment (MR
confon GmbH, 39118 Magdeburg, Germany). The headphones contain electrostatic
transducers for a broad, flat frequency response and construction-grade Peltor
earmuffs for passive damping of gradient noise. By using electrostatic rather
than pneumatic transduction, this system produces sound quality comparable to a
home stereo, with 88dB signal-to-noise ratio (SNR) and high channel separation.
During a functional MRI scanning session, sounds can be presented at
detection-threshold levels between "sparse" acquisitions or at conversational
levels (approx. 75-80 dB) during continuous scanning. Active Noise Cancellation
(ANC) in the headphones will further reduce the gradient noise and create a
quieter environment for subjects. ANC is under final pre-release testing at
MR-Confon, and the UC Davis IRC will be one of the first centers to use ANC in
fMRI research. For communication from the subject, the subject's voice
is transmitted to the scan operator via Phone-OR, an MR-compatible, optical
microphone mounted on the headphones (Magmedix, Inc., Fitchburg, MA,
01420). This microphone system suppresses gradient noise from the
transmitted audio signal, using both simple subtraction and advanced algorithms
based on speech-recognition. Combined with the MR confon system, extremely clear
bidirectional (subject to/from operator) communication is possible during
scanning to provide excellent audio SNR for voice-key applications.
